Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities to Borrowers Experiencing Financial Difficulty on Financing Receivables (Detail) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2023	Jun. 30, 2023
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 347,821	$ 640,328
Percent of total loan class		0.26%	0.48%
Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 328,513	$ 618,767
Interest Rate Reduction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		550	550
Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[2]	18,758	21,011
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 22,210	$ 64,281
Percent of total loan class		0.05%	0.14%
Commercial, Financial, Leasing, etc. [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 21,595	$ 63,393
Commercial, Financial, Leasing, etc. [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		415	415
Commercial, Financial, Leasing, etc. [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[2]	200	473
Commercial Real Estate [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 64,160	$ 179,575
Percent of total loan class		0.17%	0.49%
Commercial Real Estate [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 55,946	$ 171,361
Commercial Real Estate [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[2]	8,214	8,214
Residential Builder and Developer [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 85,008	$ 90,708
Percent of total loan class		7.49%	7.99%
Residential Builder and Developer [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 85,008	$ 90,708
Other Commercial Construction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 132,172	$ 223,094
Percent of total loan class		1.95%	3.29%
Other Commercial Construction [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 123,924	$ 214,846
Other Commercial Construction [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[2]	8,248	8,248
Residential [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 39,487	$ 72,497
Percent of total loan class		0.17%	0.32%
Residential [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 38,356	$ 69,413
Residential [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[2]	1,131	3,084
Residential Limited Documentation [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 3,776	$ 8,961
Percent of total loan class		0.38%	0.90%
Residential Limited Documentation [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 3,075	$ 8,260
Residential Limited Documentation [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[2]	701	701
Home Equity Lines and Loans [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	$ 758	$ 785
Percent of total loan class		0.02%	0.02%
Home Equity Lines and Loans [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 359	$ 359
Home Equity Lines and Loans [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		135	135
Home Equity Lines and Loans [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[2]	264	291
Recreational Finance [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	69	203
Recreational Finance [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		69	203
Automobile [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	[1]	181	$ 224
Percent of total loan class			0.01%
Automobile [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring		$ 181	$ 224

[1] Includes approximately $25 million and $48 million, respectively, of loans guaranteed by government-related entities (predominantly first lien residential mortgage loans) for the three-month and six-month periods ended June 30, 2023.

[2] Predominantly payment deferrals combined with interest rate reductions.